Using smart occupancy detection and control in buildings to reduce disease transmission

ABSTRACT

A signal is received from an occupancy sensor each time a person passes through an access point corresponding to a building space, and is identified as indicating a person either entering or exiting the building space. An occupancy count is maintained for each of the building spaces by incrementing the occupancy count when the signal indicates a person entering and decrementing the occupancy count when the signal indicates a person exiting. A determination is made as to whether the occupancy count for any of the building spaces of the plurality of building spaces has reached a threshold for the corresponding building space. Action is taken in response to determining that the occupancy count for any of the building spaces of the plurality of building spaces has reached the threshold for that particular building space.

This is a continuation of co-pending U.S. patent application Ser. No.16/907,044, filed Jun. 19, 2020, and entitled “USING SMART OCCUPANCYDETECTION AND CONTROL IN BUILDINGS TO REDUCE DISEASE TRANSMISSION”,which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates generally to facility management systems,and more particularly to systems and methods for reducing risk ofdisease spread among occupants of a building.

BACKGROUND

Infectious diseases can spread through person to person contact,touching of contaminated surfaces, exposure to air borne pathogens, aswell as other transmission mechanisms. What would be desirable aresystems and methods to help limit the spread of a disease amongoccupants of a building.

SUMMARY

The present disclosure relates generally to systems and methods forreducing risk of disease spread among occupants of a building. In oneexample, a method includes tracking occupancy within a building thatincludes a plurality of building spaces, with each building spaceincluding an access point that allows access to the building space. Eachbuilding space includes one or more sensors that provide a signal when aperson passes through the access point to the building space. A signalis received from a sensor each time a person passes through an accesspoint corresponding to a building space of the plurality of buildingspaces of the building. The signal is identified as either indicating aperson entering or exiting the building space of the plurality ofbuilding spaces. An occupancy count is maintained for each of thebuilding spaces of the plurality of building spaces by incrementing theoccupancy count when the signal indicates a person entering the buildingspace and decrementing the occupancy count when the signal indicates aperson exiting the building space. A determination is made as to whetherthe occupancy count for any of the building spaces of the plurality ofbuilding spaces has reached a threshold for the corresponding buildingspace. Action is taken in response to determining that the occupancycount for any of the building spaces of the plurality of building spaceshas reached the threshold for that particular building space.

In some cases the access point may function as a virtual fence or gate.The virtual fence may allow the system to maintain an accurate count ofthe occupants that are currently in the space without having to outfitsensors throughout the space. The lack of sensors throughout the spacemay also help increase the privacy of the occupants while in the space.

In another example, a system tracks occupancy within a building having aplurality of building spaces. The system includes a plurality of visiblelight sources distributed throughout each of at least some of theplurality of building spaces of the building, wherein each of theplurality of visible light sources is associated with (or has) acorresponding occupancy sensor, wherein when occupancy is detected, thecorresponding visible light source is turned on, and when occupancy isnot detected, the corresponding visible light source is turned off. Acontroller is operatively coupled to at least some of the occupancysensors and is configured to monitor the occupancy sensors to infer anoccupancy distribution in each of the at least some of the plurality ofbuilding spaces of the building. The controller is configured to comparethe occupancy distribution in each of the at least some of the pluralityof building spaces of the building with a corresponding occupancydistribution threshold and take action in response to determining thatthe occupancy distribution in one or more of the at least some of theplurality of building spaces of the building exceeds the correspondingoccupancy distribution threshold.

In another example, a system disinfects a space within a building thatincludes a plurality of building spaces. The system includes a pluralityof visible light sources distributed throughout each of at least some ofthe plurality of building spaces of the building, wherein each of theplurality of visible light sources is associated with a correspondingoccupancy sensor, wherein when occupancy is detected, the correspondinglight is turned on, and when occupancy is not detected, thecorresponding light is turned off. A plurality of disinfecting UV lightsources are distributed throughout each of at least some of theplurality of building spaces of the building, wherein when activated,the plurality of UV light sources disinfect at least some surfaces in acorresponding building space. A controller is operatively coupled to atleast some of the occupancy sensors and the plurality of UV lightsources. The controller is configured to monitor the occupancy sensorsto determine when one or more of the plurality of building spaces of thebuilding are unoccupied, activate one or more of the UV light sources inone or more of the plurality of building spaces of the building that aredetermined to be unoccupied, and monitor the occupancy sensors todetermine if one or more of the plurality of building spaces of thebuilding where the one or more of the UV light sources were activatedbecome re-occupied, and if so, deactivating the corresponding UV lightsources.

The preceding summary is provided to facilitate an understanding of someof the innovative features unique to the present disclosure and is notintended to be a full description. A full appreciation of the disclosurecan be gained by taking the entire specification, claims, figures, andabstract as a whole.

BRIEF DESCRIPTION OF THE FIGURES

The disclosure may be more completely understood in consideration of thefollowing description of various examples in connection with theaccompanying drawings, in which:

FIG. 1 is a schematic block diagram of an illustrative buildingmanagement system;

FIG. 2 is a schematic block diagram of an illustrative buildingmanagement system;

FIG. 3 is a schematic block diagram of an illustrative buildingmanagement system;

FIG. 4 is a schematic block diagram of an illustrative buildingmanagement system;

FIG. 5 is a schematic block diagram of an illustrative buildingmanagement system;

FIG. 6 is a flow diagram showing an illustrative method that may becarried out via the illustrative building management systems of FIGS. 1through 5;

FIG. 7 is a flow diagram showing an illustrative method that may becarried out via the illustrative building management systems of FIGS. 1through 5; and

FIG. 8 is a schematic block diagram illustrating relationships betweensensing and corresponding actions.

While the disclosure is amenable to various modifications andalternative forms, specifics thereof have been shown by way of examplein the drawings and will be described in detail. It should beunderstood, however, that the intention is not to limit the disclosureto the particular examples described. On the contrary, the intention isto cover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the disclosure.

DESCRIPTION

The following description should be read with reference to the drawings,in which like elements in different drawings are numbered in likefashion. The drawings, which are not necessarily to scale, depictexamples that are not intended to limit the scope of the disclosure.Although examples are illustrated for the various elements, thoseskilled in the art will recognize that many of the examples providedhave suitable alternatives that may be utilized.

All numbers are herein assumed to be modified by the term “about”,unless the content clearly dictates otherwise. The recitation ofnumerical ranges by endpoints includes all numbers subsumed within thatrange (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” include the plural referents unless thecontent clearly dictates otherwise. As used in this specification andthe appended claims, the term “or” is generally employed in its senseincluding “and/or” unless the content clearly dictates otherwise.

It is noted that references in the specification to “an embodiment”,“some embodiments”, “other embodiments”, etc., indicate that theembodiment described may include a particular feature, structure, orcharacteristic, but every embodiment may not necessarily include theparticular feature, structure, or characteristic. Moreover, such phrasesare not necessarily referring to the same embodiment. Further, when aparticular feature, structure, or characteristic is described inconnection with an embodiment, it is contemplated that the feature,structure, or characteristic is described in connection with anembodiment, it is contemplated that the feature, structure, orcharacteristic may be applied to other embodiments whether or notexplicitly described unless clearly stated to the contrary.

FIG. 1 is a schematic block diagram of an illustrative buildingmanagement system 10. The illustrative building management system 10 isinstalled in a building 12 and may be considered as being configured toreduce the risk of pathogenic exposure within the building 12. Thebuilding 12 includes a number of building spaces 14 that areindividually labeled as 14 a, 14 b, 14 c. It will be appreciated thatthis is merely illustrative, as the building 12 will typically include amuch greater number of building spaces 14 or zones. At least some of thebuilding spaces 14 may periodically have one or more people within thebuilding space 14. In some cases, the building 12 may be a hotel, andthus the building spaces 14 may be individually rentable guest rooms.The building 12 may be an office building, or a portion of an officebuilding, and thus the building spaces 14 may be individual offices orwork spaces. In some case, the disclosure may be applied to a cruiseship.

Each of the building spaces 14 includes one or more occupancy sensors16, although only one occupancy sensor 16 is shown in each of thebuilding spaces 14. The occupancy sensors 16 are individually labeled as16 a, 16 b, 16 c. At least some of the occupancy sensors 16 may be PIRsensors, mmWave sensors, motion sensors and/or microphones, for example.Some of the occupancy sensors 16 may be part of a security system of thebuilding 12, for example. In some cases, some of the occupancy sensors16 may be video cameras that are coupled with video analytics to detectthe presence of one or more people, and hence determine occupancy.Occupancy detection may include detecting the presence of people,including counting people. Occupancy detection may also includebehavioral indicators such as hand washing, signs of illness such asfever and coughing, spacing between people and the like.

Each of the building spaces 14 also include one or more environmentalsensors 18, although only one environmental sensor 18 is shown in eachof the building spaces 14. The environmental sensors 18 are individuallylabeled as 18 a, 18 b, 18 c. The environmental sensors 18 may, forexample, be sensors such as temperature sensors, humidity sensors,visible light sensors, UV sensors, particulate matter sensors (e.g.PM2.5, PM10), VOC sensors, airborne and waterborne pathogen sensors, COsensors, CO2 sensors, ozone sensors, and/or any other environmentalsuitable sensor. In some cases, some of the environmental sensors 18 maybe considered as being Indoor Air Quality (IAQ) sensors. In some cases,one or more of the environmental sensors 18 may be disposed within aroom thermostat within at least some of the building spaces 14.

In some cases, sensing environmental parameters may include sensing airpressure in general, and air pressure differentials across the building12 in particular. It has been found that air pressure differentials canprovide a general indication of air flow through the building 12. Airfill flow from an area of higher pressure to an area of lower pressure,for example. Measuring air pressure differentials can also provide anindication of how opening and closing windows and doors can influenceair flow through the building 12, for example. Measuring air pressuredifferentials can also provide an indication of the impact of turningventilation on or off, or turning ventilation rates up and down, amongother HVAC capabilities. In some cases, controlled air flow is one ofthe key techniques highlighted by ASHRAE (American Society of Heating,Refrigerating and Air Conditioning Engineers) to control airbornepathogen transmission.

If a building space 14 is in a hospital operating room, for example,there is a desire to maintain an air pressure within the operating roomthat is higher than the air pressure in neighboring spaces. This canhelp to limit airborne pathogens from entering the operating room, asany air movement will tend to be from inside the operating room tooutside of the operating room. If a building space 14 is not occupied,there may be a desire to reduce air flow in the duct(s) that provideconditioned air to the building space 14 in order to increase an amountof time that any airborne pathogens are exposed to UV light during asanitizing process. These are just examples.

Each of the building spaces 14 includes one or more controllablebuilding components 20, although only one controllable buildingcomponent 20 is shown in each of the building spaces 14. Each of thecontrollable building components 20 may be considered as beingconfigured to control environmental conditions within the buildingspaces 14 in order to reduce the likelihood of disease transmissionamong occupants of the building 12. At least some of the controllablebuilding components 20 may include heating, ventilating and airconditioning system (HVAC) components such as heating sources, coolingsources, ventilation sources, humidifiers and dehumidifiers, asexamples. At least some of the controllable building components 20 mayinclude a disinfecting component. Examples of disinfecting componentsinclude sources of UV light that may be used to sanitize surfaces withinthe building space 14. UV light sources may also be used to disinfectcomponents of an HVAC system, such as but not limited to disinfectingfilters within the HVAC system. This may include cleaning filter mediaas well as electrostatic filters.

The UV light spectrum ranges from about 100 nanometers (nm) to about 400nm. The UV light spectrum includes UV-A, which ranges from 315 nm to 400nm. This UV light spectrum also includes UV-B, which ranges from 280 nmto 315 nm. UV-C, which ranges from 200 nm to 280 nm, is particularlyeffective for disinfecting. There is also Far-UVC, which ranges from 207nm to 222 nm and thus is a subset of the UV-C light spectrum. Far-UVC isalso particularly effective for disinfecting, and is believed to be safefor human skin and eyes. The UV light spectrum also includes VUV Far-UV,which ranges from 100 nm to 200 nm. In some cases, at least some of thecontrollable building components 20 may include a source of UV-C lightthat is configured to provide UV-C light for a period of time sufficientto disinfect surfaces within the building space 14. For example, it maytake a period of time, such as 5 minutes, 10 minutes, 30 minutes, 1hour, 2 hours, 3 hours or more, depending on a number of factors such asthe intensity of the UV-C light source and the distance between the UV-Clight source and the surfaces to be sanitized.

In the example shown, each of the occupancy sensors 16, each of theenvironmental sensors 18 and each of the controllable buildingcomponents 20 are operably coupled with a building network 22. Acontroller 24 is operably coupled with the building network 22 such thatthe controller 24 is able to receive occupancy data from the occupancysensors 16 and indoor air quality data from the environmental sensors18. Accordingly, each of the one or more occupancy sensors 16 may beconsidered as providing occupancy signals over the building network 22.Similarly, each of the one or more environmental sensors 18 may beconsidered as providing air quality parameter signals over the buildingnetwork 22. In some cases, the one or more environmental sensors 18 mayprovide a measurement of carbon dioxide concentration as a basicoccupancy indicator. It will be appreciated that carbon dioxideconcentration will increase as additional people are present within thebuilding space 14, and will decrease as people leave the building space14.

The controller 24 is also able to provide control signals to thecontrollable building components 20 via the building network 22. It iscontemplated that the building network 22 may be a wired network, awireless network or a combination of wired and wireless. It will beappreciated that while the controller 24 is shown as being locatedinside of the building 12, this is not required in all cases. In someinstances, the controller 24 may itself be manifested within one or morecomputing devices that may be local to the building 12 or may be remotefrom the building 12. In some case, all or part of the controller 24 maybe manifested within a cloud-based server.

In some instances, the controller 24 is configured to receive occupancysignals from the one or more occupancy sensors 16 over the buildingnetwork 22 and to receive indoor air quality parameter signals from theone or more environmental sensors 18 over the building network 22. Thecontroller 24 is configured to process the received occupancy signalsand the received indoor air quality parameter signals (sometimes incombination) to determine whether action is needed to improve one ormore environmental conditions within at least some of the plurality ofbuilding spaces 14 in order to reduce the likelihood of diseasetransmission among occupants of the building 12. Responsive todetermining that action is needed, the controller 24 is configured tosend control signals to one or more of controllable building componentsover the building network to improve one or more environmentalconditions within at least some of the plurality of building spaces toreduce the likelihood of disease transmission among occupants of thebuilding.

In some instances, the controller 24 is configured to process one ormore of the received occupancy signals to identify a measure ofcompliance of one or more of the occupants of the building 12 with oneor more predefined behavioral standards. In some cases, the occupancysignals may include locating sensors that can report a location of theone or more occupants of the building. The locating sensors may include,for example, Bluetooth or WiFi beacons that can be used to track anoccupants phone's location in the building. It is contemplated that thelocating sensor may be any locating sensor or system that is canidentify a location of the one or more occupants in the building. Insome cases, the occupancy signals may include video signals from a videocamera or signals from an indoor radar sensor (e.g. mmWave sensor) thatcan be used to identify compliance of one or more of the occupants ofthe building 12 with one or more predefined behavioral standards. Theseare just examples.

One example of a predefined behavioral standard includes a socialdistancing standard. In some instances, maintaining a minimum distancebetween people may help prevent the transmission of disease. Socialdistancing can help reduce or limit the spread of disease from bothsymptomatic and asymptomatic carriers. The social distancing standardmay be set to a particular physical distance that individuals shouldstrive to maintain between themselves and other individuals, and may bedetermined at least in part upon the particular environment. Peopleproduce aerosols when talking, breathing, coughing and the like. Ifpeople stay far enough apart, these aerosols are able to drop out of theair before they reach another person who could inhale the aerosol andbecome infected. Relative humidity can impact how far an aerosol cantravel. As an example, a social distancing standard may be set equal to6 feet, or 12 feet.

Another example of a predefined behavioral standard includes a maximumpeople per building space standard. This may be equivalent to themaximum capacity for a particular building space 14, such as dictated byfire code. The maximum people per building space standard may dictate areduced maximum capacity, particularly during times in which aparticular pathogen is believed to be active. For example, the maximumpeople per building space standard during times in which pathogens areactive may be set equal to fifty percent of the maximum occupancydictated by fire code. The maximum people per building space standardmay be set equal to twenty five percent the maximum occupancy dictatedby fire code. These are just examples, as these numbers may varydepending on the communicability of a particular pathogen, thesusceptibility of the people within the building 12 to the particularpathogen, and the like.

As another example, a predefined behavioral standard may include ahygiene standard. Examples of hygiene standards include whetherindividuals are wearing masks, particularly if the people are inside thebuilding 12 and are not always complying with social distancingstandards. Hygiene standards may also dictate whether a mask is requiredbased upon how long two people may be in proximity to each other, aslength of exposure can influence the degree or likelihood of pathogentransmission. The longer a person is exposed to a carrier, for example,the more of the pathogen that the person will have likely been exposedto and thus may now possess. Another example of a hygiene standardinvolves hand washing. This may be as simple as requiring that peoplewash their hands after using the bathroom. This may also includerequiring people to wash their hands each time they move from one spaceto another space, or are about to eat or drink something, for example.Hand washing standards may specify a duration of time that hand washingis expected to last in order to be effective. For example, a handwashing time of twenty seconds is contemplated. Hygiene standards mayalso include specifying whether people are wearing gloves, as well asdetails regarding when, where and how the person is expected to weargloves. A predefined behavioral standard may include ascertainingcompliance with hygiene standards such as but not limited to wearinggloves, wearing masks, and hand washing.

In some instances, a predefined behavioral standard may include asymptoms standard. Depending on a suspected pathogen or a resultingdisease, it will be appreciated that symptomatic individuals with thesuspected pathogen or disease may have any of a variety of differentsymptoms. For example, various respiratory diseases may have symptomsthat include coughing and/or sneezing. An elevated body temperature,better known as a fever, is also a common disease symptom as in manycases, the elevated body temperature is the result of the person'simmune system trying to fight off the pathogen.

In some instances, a predefined behavioral standard may include acleaning standard that is associated with a cleaning crew. This mayinclude, for example, whether the correct area gets cleaned when thatarea is supposed to get cleaned. This may include whether the actualduration of the cleaning process meets or exceeds a cleaning timestandard for that particular building space, for that particularcleaning crew and the like. Cleaning standards may also refer toautomated cleaning and disinfecting processes, such as but not limitedto an expected duration for exposing a surface or surfaces to UV-Clight, for example. A disinfecting process may be set to last aparticular length of time, but can be interrupted if a door is openedprematurely, for example. In some instances, the sensing controls may beintegrated into a workflow application in order to provide a cleaningscore or map that provides real-time insights to the cleaning staff.This may facilitate the cleaning staff being able to identify and takecare of any missed spots, for example.

The controller 24 may be configured to process one or more of thereceived occupancy signals to identify a measure of a total number ofoccupants within one or more of the plurality of building spaces 14 ofthe building 12, and may use the measure of the total number ofoccupants within one or more of the plurality of building spaces 14 ofthe building 12 to determine whether action is needed. In some cases,the controller 24 may be configured to determine when action is neededby one or more persons to improve one or more environmental conditionswithin at least some of the plurality of building spaces 14 to reducethe likelihood of disease transmission among occupants of the building12, and provide a notification. In some cases, the controller 24 may beconfigured to track occupancy over time, and thus may be able to learnwhen particular building spaces 14 are expected to remain empty.

In some instances, the controller 24 may be configured to determine thataction is needed to maintain the indoor air quality when one or moreindoor air quality parameters exceed a threshold for the correspondingone or more indoor air quality parameters, and in response, thecontroller 24 may be configured to output appropriate control signalsrequesting, for example, an increase in fresh air to the building space14, an increase or decrease in a temperature and/or humidity level,and/or any other suitable change to the environment.

In some cases, the controller 24 may be configured to determine thataction is needed to maintain the indoor air quality when one or more ofthe building spaces 14 have an indicated occupancy that is above a firstoccupancy threshold, and in response, the controller 24 may beconfigured to output appropriate control signals requesting, forexample, an increase in fresh air to the building space 14, an increaseor decrease in a temperature and/or humidity level, and/or any othersuitable change to the environment. The controller 24 may be configuredto determine that action is needed to maintain the indoor air qualitywhen one or more of the building spaces 14 have an indicated occupancythat is at a second occupancy threshold, and in response, the controller24 may be configured to output appropriate control signals indicatingthat no additional people are permitted in the one or more buildingspaces. The control signals may include instructions for an audio and/orvisual warning that occupancy has reached the second threshold, and/orinstructions to lock one or more doors in order to prevent additionalpeople from entering the one or more building spaces.

In some instances, the controller 24 may be configured to process one ormore of the received indoor air quality parameter signals to identify ameasure of compliance with one or more air quality standards. Examplesair quality standards include a relative humidity standard and atemperature standard. Other examples of air quality standards include acarbon dioxide (CO₂) standard, a carbon monoxide (CO) standard, aParticulate Matter (PM) standard, a pathogen concentration standard, aVolatile Organic Compound (VOC) standard, a H2CO standard.

FIG. 2 is a schematic block diagram of an illustrative buildingmanagement system 30. The illustrative building management system 30 isshown as being installed in the building 12 and may be considered asbeing configured to reduce the risk of pathogenic exposure within thebuilding 12. The building 12 includes a number of building spaces 32that are individually labeled as 32 a, 32 ab, 32 c. It will beappreciated that this is merely illustrative, as the building 12 willtypically include a much greater number of building spaces 32 or zones.At least some of the building spaces 32 may periodically have one ormore people within the building space 32. In some cases, at least someof the building spaces 32 may be considered as being examples of thebuilding spaces 14. At least some of the building spaces 32 may includefeatures ascribed to the building spaces 14. At least some of thebuilding spaces 14 may include features ascribed to the building spaces32.

In addition to the occupancy sensors 16, each of the building spaces 32include one or more sanitizers 34, although only one sanitizer 34 isshown in each of the building spaces 32. The sanitizers are individuallylabeled as 34 a, 34 b, 34 c. In some cases, the sanitizers 34 may eachbe sources of UV-C light. The sanitizers 34 may be considered as beingpositioned to sanitize surfaces within a corresponding building space32. Disinfecting with other processes such as plasma and ionization isalso contemplated. Each of the one or more occupancy sensors 16 may beconsidered as being positioned to detect occupancy within each of theplurality of building spaces 32, and may be considered as being operablyconnected to the building network 22. The controller 24 is configured toreceive occupancy signals from the one or more occupancy sensors 16 andto process the occupancy signals to determine whether a particularbuilding space 32 is due to be sanitized and is currently available tobe sanitized. In some cases, determining whether the particular buildingspace 32 is due to be sanitized is based at least in part upon how longit has been since that particular building space 32 was last sanitizedand/or how many people have been in that particular building space 32since it was last sanitized. In response to determining that theparticular building space 32 is due to be sanitized and is currentlyavailable to be sanitized, the controller 24 outputs appropriate controlsignals to one or more of the one or more sanitizers 34 to proceed withsanitizing the particular building space 32.

FIG. 3 is a schematic block diagram of an illustrative buildingmanagement system 40. The illustrative building management system 40 isshown as being installed in the building 12 and may be considered asbeing configured to disinfect spaces within the building 12. Thebuilding 12 includes a number of building spaces 42 that areindividually labeled as 42 a, 42 ab, 42 c. It will be appreciated thatthis is merely illustrative, as the building 12 will typically include amuch greater number of building spaces 42 or zones. At least some of thebuilding spaces 42 may periodically have one or more people within thebuilding space 42. In some cases, at least some of the building spaces42 may be considered as including features ascribed to the buildingspaces 14 and/or the building spaces 32. At least some of the buildingspaces 14 and 32 may include features ascribed to the building spaces42.

In addition to the occupancy sensors 16, each of the building spaces 42include one or more visible light sources 44, although only one visiblelight source 44 is shown in each of the building spaces 42. The visiblelight sources 44 are individually labeled as 44 a, 44 b, 44 c. Thevisible light sources 44 may be considered as being distributedthroughout each of at least some of the plurality of building spaces 42of the building 12, wherein each of the plurality of visible lightsources 44 is associated with a corresponding occupancy sensor 16,wherein when occupancy is detected, the corresponding visible lightsource 44 is turned on, and when occupancy is not detected, thecorresponding visible light source 44 is turned off. In some instances,some of the occupancy sensors 16 may be integrated into a correspondingvisible light source 44.

In some instances, the controller 24 may be configured to monitor theoccupancy sensors 16 to infer an occupancy distribution in each of theat least some of the plurality of building spaces 42 of the building 12and to compare the occupancy distribution in each of the at least someof the plurality of building spaces 42 of the building 12 with acorresponding occupancy distribution threshold. The controller 24 may beconfigured to take action in response to determining that the occupancydistribution in one or more of the at least some of the plurality ofbuilding spaces 42 of the building 12 exceeds the correspondingoccupancy distribution threshold. Taking action may, for example,include providing an audio and/or visual warning that the occupancydistribution in one or more of the at least some of the plurality ofbuilding spaces 42 of the building 12 exceeds the correspondingoccupancy distribution threshold. This is just an example. In somecases, the occupancy distribution threshold of one of the plurality ofbuilding spaces 42 may be different from the occupancy distributionthreshold of another one of the plurality of building spaces 42.

FIG. 4 is a schematic block diagram of an illustrative buildingmanagement system 50. The illustrative building management system 50 isshown as being installed in the building 12 and may be considered asbeing configured to disinfect spaces within the building 12. Thebuilding 12 includes a number of building spaces 52 that areindividually labeled as 52 a, 52 ab, 52 c. It will be appreciated thatthis is merely illustrative, as the building 12 will typically include amuch greater number of building spaces 52 or zones. At least some of thebuilding spaces 52 may periodically have one or more people within thebuilding space 52. In some cases, at least some of the building spaces52 may be considered as including features ascribed to the buildingspaces 14 and/or the building spaces 32 and/or the building spaces 42.At least some of the building spaces 14, 32 and 42 may include featuresascribed to the building spaces 52.

In addition to the visible light sources 44 and the occupancy sensors16, each of the building spaces 52 includes one or more UV light sources54, although only one UV light source 54 is shown within each of thebuilding spaces 52. The UV light sources 54 may be UV-C light sources,for example. The UV light sources 54 are individually labeled as 54 a,54 b, 54 c. Each of the visible light sources 44 are associated with acorresponding occupancy sensor 16 such that when occupancy is detected(by a particular occupancy sensor 16) the corresponding visible lightsource 44 is turned on, and when occupancy is not detected, thecorresponding visible light source 44 is turned off.

The controller 24 is operably coupled to at least some of the occupancysensors 16 and the plurality of UV light sources 54. In some instances,the controller 24 is configured to monitor the occupancy sensors 16 todetermine when one or more of the plurality of building spaces 52 of thebuilding 12 are unoccupied. The controller 24 may activate one or moreof the UV light sources 54 in one or more of the plurality of buildingspaces 52 of the building 12 that are determined to be unoccupied. Insome instances, the controller 24 may further determine when one or moreof the plurality of building spaces 52 of the building 12 are unoccupiedand are expected to remain unoccupied for at least a predeterminedperiod of time based at least in part on a historical occupancy pattern.

In some cases, the controller 24 may activate the one or more UV lightsources 54 for a predetermined period of time. The predetermined periodof time may be user-adjustable, for example, by building management forthe building 12. The predetermined period of time may be set when thesystem 50 is initially configured. The controller 24 may monitor theoccupancy sensors 16 to determine if one or more of the plurality ofbuilding spaces 52 of the building 12 where the one or more of the UVlight sources 54 were activated become re-occupied, and if so,deactivating the corresponding UV light sources 54. This can helpprevent an individual walking into the building space 52 from beingexposed to possibly damaging UV light. In some instances, the buildingspace 52 may include a UVC sensor (not shown) that provides additionalfeedback to the controller 24 that an active UV light source is present,such that the controller 24 can provide a warning that the UV lightsource is active, and that the controller 24 can shut off the UV lightsource if occupancy is detected. In some cases, a signal from the UVCsensor can be taken into account when tracking disinfection statisticsincluding how frequently and/or the duration of disinfecting processes.

FIG. 5 is a schematic block diagram of an illustrative buildingmanagement system 60. The illustrative building management system 60 isshown as being installed within the building 12. The building 12includes a number of building spaces 62 that are individually labeled as62 a, 62 ab through 62 n. At least some of the building spaces 62 mayperiodically have one or more people within the building space 62. Insome cases, at least some of the building spaces 62 may be considered asincluding features ascribed to the building spaces 14 and/or thebuilding spaces 32 and/or the building spaces 42 and/or the buildingspaces 52. At least some of the building spaces 14, 32, 42 and 52 mayinclude features ascribed to the building spaces 62.

Each building space 62 includes at least one access point 64, althoughonly one access point 64 is shown within each of the building spaces 62.The access points 64 are individually labeled as 64 a, 64 b through 64n. In some cases, a building space 62 may have more than one accesspoint 64. In simplest terms, the access point 64 may be a physical orvirtual door that allows people to enter and/or exit the building space62. In some cases, the physical or virtual door can be closed to preventadditional people from passing through the access point 64 and enteringthe building space 62. An access point 64 may be a designated region ofa hallway, elevator, lobby or the like, that can be considered asproviding access to a particular building space 62.

Each building space 62 includes at least one sensor 66, although onlyone sensor 66 is shown in each of the building spaces 62. The sensors 66are individually labeled as 66 a, 66 b through 66 n. In some cases,there may be one sensor 66 that is associated with each of the accesspoints 64. The sensors 66 may be configured to output a signal thatindicates that someone has passed through an access point 66, eitherentering the building space 62 or exiting the building space 62. In somecases, at least some of the sensors 66 may include smart floor sensorsthat a person walks across. As the person walks across the smart floorsensor, a pressure signal is outputted that can indicate a direction oftravel (i.e., into the building space 62 or out of the building space62). The pressure signal may, for example, enable analysis that yields ashape or transient characteristics of a pressure input made by theperson's foot, and thus a direction of travel can be determined. Thesmart floor sensor(s) can be embedded in a floor covering, such as butnot limited to an area rug or mat. Thus, they can easily be used in ahallway to define an access point 64 (and corresponding sensor 66). Insome cases, the smart floor sensor is large enough that a person passingthrough the access point 64 has to take multiple steps crossing thesmart floor sensor. As a result, the direction of their travel is easilydetermined.

In some cases, at least some of the sensors 66 may include passiveinfrared (PIR) sensors. By placing two or more PIR sensors in thebuilding space 62, it is possible to determine a direction of travel fora person passing through the access point 64. In some instances, atleast some of the sensors 66 may include augmented PIR sensors that areconfigured to provide output signals that can indicate one or more ofdirection, distance and speed of a person traveling through the accesspoint 64. In some cases, a building space 62 may include both a smartfloor sensor and a PIR sensor as the sensors 66, such that a signal fromone of the sensors 66 may be used as a check or confirmation of a signalfrom the other of the sensors 66. In some cases, at least some of thesensors 66 may include RFID card readers that can read an access cardcarried by a person without requiring the person to physically scan theaccess card. One or more of the sensors 66 may include a time of flightsensor that is based on a laser bean interruption, or a video camera.These are just some examples. With these and other types of sensors, theoccupants can be granted frictionless access to a particular buildingspace 62.

In some cases, Time of Flight (ToF) may be implemented as a technologythat can count people moving through the access point 64. ToF canprovide accurate people counting at low to medium traffic density, suchas may occur when several people walk into a room at around the sametime. ToF involves creating a pair of sensor zones, such as a front zoneand a back zone. A person is detected as they cross through both thefront zone and the back zone. In some instances, the sensors used forToF measurements may be placed behind an optically opaque polymer panel.This can mean that ToF can be implemented unobtrusively, without peoplerealizing that they are walking past a sensor, or even realizing thatthey are being counted.

In some instances, the controller 24 maintains a counter 68 for each ofthe access points 64. The controller 24 may include a counter 68 a thatcorresponds to the sensor 66 a, a counter 68 b that corresponds to thesensor 66 b, all the way through a counter 68 n that corresponds to thesensor 66 n. The appropriate counter 68 may be incremented in responseto the controller 24 receiving an indication from a particular sensor 66that a person has entered the particular building space 62 through thataccess point 64 and may be decremented in response to the controller 24receiving an indication from a particular sensor 66 that a person hasexited the particular building space 62 through that access point 64.

Once a particular counter 68 has reached a particular threshold, thecontroller 24 may take appropriate action. In some cases, taking actionin response to the counter 68 reaching a threshold may include issuingan audio and/or visual warning that current occupancy within aparticular building space 62 has reached the threshold for thatparticular building space 62. Taking action may, for example, includesecuring the access point 66 for the particular building space 62 suchthat people are allowed to exit the building space 62 but are notallowed to enter the building space 62 until the occupancy counter 68for that particular building space 62 drops below the threshold. In somecases, taking action may include increasing an air ventilation rate forthat building space 62.

FIG. 6 is a flow diagram showing an illustrative method 70 for trackingoccupancy within a building that includes a plurality of buildingspaces, with each building space including an access point that allowsaccess to the building space and a sensor that provides a signal when aperson passes through the access point. A signal is received from asensor each time a person passes through an access point correspondingto a building space of the plurality of building spaces of the building,as indicated at block 72. The signal is identified as either indicatinga person entering or exiting the building space of the plurality ofbuilding spaces, as indicated at block 74. An occupancy count ismaintained for each of the building spaces of the plurality of buildingspaces by incrementing the occupancy count when the signal indicates aperson entering the building space and decrementing the occupancy countwhen the signal indicates a person exiting the building space, asindicated at block 76. A determination may be made that the occupancycount for any of the building spaces of the plurality of building spaceshas reached a threshold for the corresponding building space, asindicated at block 80.

In response to determining that the occupancy count for any of thebuilding spaces of the plurality of building spaces has reached thethreshold for that particular building space, action is taken, asindicated at block 80. Taking action may, for example, include issuingan audio and/or visual warning that current occupancy within aparticular building space of the plurality of building spaces hasreached the threshold for that particular building space. In someinstances, taking action includes securing the access point for theparticular building space of the plurality of building spaces such thatpeople are allowed to exit but are not allowed to enter until theoccupancy count for that particular building space drops below thethreshold. Taking action can additionally or alternatively includeincreasing an air ventilation rate for the particular building space ofthe plurality of building spaces.

In some cases, the sensor associated with the access point of at leastone of the building spaces of the plurality of building spaces mayinclude a smart floor sensor embedded in a floor covering. The sensorassociated with the access point of at least one of the building spacesof the plurality of building spaces may include a passive infrared (PIR)sensor. The sensor associated with the access point of at least one ofthe building spaces of the plurality of building spaces may include anRFID card reader that can read an access card carried by a personwithout requiring the person to physically scan the access card toprovide frictionless access through the corresponding access point.

The sensor associated with the access point of at least one of thebuilding spaces of the plurality of building spaces may include a videocamera having a field of view that includes at least part of thecorresponding access point, wherein video analytics are applied toidentify the signal from the video camera as either indicating a personentering or exiting the building space of the plurality of buildingspaces. The video analytics may include identifying biometricidentification. The video analytics may include identifying compliancewith one or more behavioral thresholds such as but not limited to one ormore of a social distancing compliance threshold, a hand hygienecompliance threshold and a Personal Protective Equipment (PPE)compliance threshold.

The access point may, for example, include one of a building entry, anemergency exit, a door or hall to a room or zone, an elevator, and astair case. At least one of the access points may further include ahealth screening sensor for performing a health screen of a personpassing through the access point, wherein the health screening sensorcomprises one or more or a video camera, a thermal camera and amicrophone.

FIG. 7 is a flow diagram showing an illustrative method 90 ofmaintaining a level of occupant safety within a building having abuilding space, the building space including an occupancy sensor and oneor more air quality sensors, the building space serviced by a heating,ventilating and air conditioning (HVAC) system, each of the sensors andthe HVAC system operably coupled with a building network. Occupancysignals are received from the occupancy sensor, as indicated at block92. Indoor air quality parameter signals are received from the one ormore indoor air quality sensors, as indicated at block 94. The occupancysignals and the indoor air quality parameter signals are processed todetermine whether action is needed to maintain the level of safetywithin the building space, as indicated at block 96. Responsive todetermining that action is needed, control signals are outputted to theHVAC system via the building network, as indicated at block 98.

In some cases, the building space may be serviced by a sanitizingdevice. The method 90 may further include tracking occupancy data fromthe one or more occupancy sensors over time in order to learn when thebuilding space is expected to not be occupied for a period of time longenough to sanitize the building space, as optionally indicated at block100. A determination may be made that the building space is notcurrently occupied, as optionally indicated at block 102. Adetermination may be made that a current time corresponds to when thebuilding space is expected to not be occupied for a period of time longenough to sanitize the building space, as optionally indicated at block104. In some cases, and as optionally indicated at block 106,instructions may be provided via the building network to the sanitizingdevice to proceed with sanitizing surfaces within the building space. Insome cases, a warning may be issued via the building network that thebuilding space is currently being sanitized.

FIG. 8 is a schematic block diagram illustrating relationships betweensensing and corresponding actions. On the far left are possible inputs120. As shown, the possible inputs 120 may include people, as indicatedby a people icon 122. The possible inputs 120 may include environmentalconditions, as represented by a wind icon 124. In some cases, thepossible inputs 120 may include a pathogen, as indicated by the pathogenicon 126. These possible inputs 120 may be sensed via a sensing section128. The sensing section 128 may include a smart occupancy sensing block130 and an environmental sensing block 132. Possible outputs from thesmart occupancy sensing block 130 may include one or more of occupancynumbers for a zone, as well as possibly detected symptoms within thezone such as coughing. Possible outputs from the smart occupancy sensingblock 130 may also include occupancy detection that might cause lightingto be turned on or off, for example. In some cases, a degree ofhysteresis or a short delay may be implemented in order to prevent apossible situation in which the lights turn on and off while a personlingers in the doorway, for example, which can be hard on lightingequipment and may be uncomfortable for the person in the doorway. Evenif hysteresis is implemented with respect to lighting control, the smartoccupancy sensing block 130 may immediately report occupancy.

Possible outputs from the environmental sensing block 132 may includedetection of airborne pathogens. Possible outputs from the environmentalsensing block 132 may include any of a variety of different air qualityparameters such as but not limited to particulate matter (PM), airpressure, temperature, relative humidity, carbon dioxide concentration,PM2.5, total volatile organic compound (TVOC) concentration, carbonmonoxide concentration, H2CO (formaldehyde) concentration, and the like.

An actions section 134 includes a number of different possible actions.It will be appreciated that, as shown, the inputs to individual blockswithin the actions section 134 (the possible outputs from the sensingsection 128) can vary, depending on the specific actions block. Forexample, the actions section 134 includes a Microbial Detection andPathogen Identification block 136 that receives sensed data pertainingto sensed airborne pathogens. The actions section 134 includes anOccupant-centric HVAC and UVC Controls block 138. As can be seen, theOccupant-centric HVAC and UVC Controls block 138 can receive a number ofdifferent inputs, including occupancy data from the Smart OccupancySensing block 130 and a number of air quality parameters from theEnvironmental Sensing block 132. The actions section 134 also includesan Alerts/Notifications block 140 and an Occupant Screening block 142.The Alerts/Notifications block 140 may output information pertaining tomaximum allowed occupancy, physical distancing between people, contacttracing and compliance to hygiene standards. The Occupant Screeningblock 142 may output information related to touchless or biometricaccess and detecting symptoms of illness.

An analytics section 144 includes an Alarms block 146 and a PredictiveMaintenance block 148. Illustrative outputs from the Alarms block 146and the Predictive Maintenance block 148 are listed. A Reports block 150and a Certification block 152 can output regulatory reports anddata-driven improvement plans, respectively, as shown. AnAlerts/Notifications block 154 can output information to a dashboard. ASafe UVC Operation block 158 confirms that UVC sterilization only occursin unoccupied spaces.

Having thus described several illustrative embodiments of the presentdisclosure, those of skill in the art will readily appreciate that yetother embodiments may be made and used within the scope of the claimshereto attached. It will be understood, however, that this disclosureis, in many respects, only illustrative. Changes may be made in details,particularly in matters of shape, size, arrangement of parts, andexclusion and order of steps, without exceeding the scope of thedisclosure. The disclosure's scope is, of course, defined in thelanguage in which the appended claims are expressed.

What is claimed is:
 1. A method of tracking occupancy within a building,the building including a plurality of building spaces, each buildingspace of the plurality of building spaces including an access point thatallows access to the building space and a sensor that provides a signalwhen a person passes through the access point, the method comprising:maintaining an occupancy count for each of the building spaces of theplurality of building spaces; determining when the occupancy count forany of the building spaces of the plurality of building spaces reaches athreshold for the corresponding building space; and taking action inresponse to determining that the occupancy count for any of the buildingspaces of the plurality of building spaces has reached the threshold forthat particular building space, wherein taking action comprisescontrolling one or more building management systems of the building toalter one or more conditions of the particular building space to reducea likelihood of disease transmission among occupants of the particularbuilding space.
 2. The method of claim 1, further comprising: receivinga signal from a Time of Flight (ToF) sensor each time a person passesthrough an access point corresponding to a building space of theplurality of building spaces of the building; identifying the signal aseither indicating a person entering or exiting the building space of theplurality of building spaces; and maintaining the occupancy count foreach of the building spaces of the plurality of building spaces byincrementing the occupancy count when the signal indicates a personentering the building space and decrementing the occupancy count whenthe signal indicates a person exiting the building space.
 3. The methodof claim 1, wherein controlling the one or more building managementsystems of the building to alter one or more conditions of theparticular building space to reduce the likelihood of diseasetransmission among occupants of the particular building space comprisescontrolling the one or more building management systems of the buildingto increase a fresh air ventilation rate to the particular buildingspace.
 4. The method of claim 3, wherein controlling the one or morebuilding management systems of the building to alter one or moreconditions of the particular building space to reduce the likelihood ofdisease transmission among occupants of the particular building spacecomprises controlling the access point for the particular building spacesuch that people are allowed to exit the particular building space butare not allowed to enter until the occupancy count for that particularbuilding space drops below the threshold.
 5. The method of claim 1,wherein controlling the one or more building management systems of thebuilding to alter one or more conditions of the particular buildingspace to reduce the likelihood of disease transmission among occupantsof the particular building space comprises controlling the one or morebuilding management systems of the building to change the airtemperature in the particular building space.
 6. The method of claim 1,wherein controlling the one or more building management systems of thebuilding to alter one or more conditions of the particular buildingspace to reduce the likelihood of disease transmission among occupantsof the particular building space comprises controlling the one or morebuilding management systems of the building to change the humidity inthe particular building space.
 7. The method of claim 1, whereincontrolling the one or more building management systems of the buildingto alter one or more conditions of the particular building space toreduce the likelihood of disease transmission among occupants of theparticular building space comprises controlling the access point for theparticular building space such that people are allowed to exit theparticular building space but are not allowed to enter until theoccupancy count for that particular building space drops below thethreshold.
 8. The method of claim 1, further comprising: receiving asignal from sensor each time a person passes through an access pointcorresponding to a building space of the plurality of building spaces ofthe building; identifying the signal as either indicating a personentering or exiting the building space of the plurality of buildingspaces; and maintaining the occupancy count for each of the buildingspaces of the plurality of building spaces by incrementing the occupancycount when the signal indicates a person entering the building space anddecrementing the occupancy count when the signal indicates a personexiting the building space.
 9. The method of claim 8, wherein the sensorcomprises a smart floor sensor embedded in a floor covering.
 10. Themethod of claim 8, wherein the sensor comprises a passive infrared (PIR)sensor.
 11. The method of claim 8, wherein the sensor comprises an RFIDcard reader that can read an access card carried by a person withoutrequiring the person to physically scan the access card to providefrictionless access through the access point.
 12. The method of claim 8,wherein the sensor comprises a video camera having a field of view thatincludes at least part of access point, wherein video analytics areapplied to identify whether a person is entering or exiting the buildingspace of the plurality of building spaces.
 13. The method of claim 12,wherein the video analytics include identifying compliance whether aperson is complying with one or more of a social distancing metric and aPPE matric.
 14. The method of claim 8, wherein the access point furthercomprises a health screening sensor for performing a health screen of aperson passing through the access point, wherein the health screeningsensor comprises one or more or a video camera, a thermal camera and amicrophone.
 15. A system for tracking occupancy within a building, thebuilding including a plurality of building spaces, the systemcomprising: a plurality of visible light sources distributed throughouteach of at least some of the plurality of building spaces of thebuilding, wherein each of the plurality of visible light sourcesincludes a corresponding occupancy sensor; a controller operativelycoupled to at least some of the occupancy sensors, the controllerconfigured to: monitor the occupancy sensors to infer an occupancydistribution in each of the at least some of the plurality of buildingspaces of the building; compare the occupancy distribution in each ofthe at least some of the plurality of building spaces of the buildingwith a corresponding occupancy distribution threshold; and take actionin response to determining that the occupancy distribution for any ofthe building spaces of the plurality of building spaces has reached thecorresponding occupancy distribution threshold for that particularbuilding space, wherein taking action comprises controlling an HVACsystem of the building to alter one or more environmental conditions ofthe particular building space to reduce a likelihood of diseasetransmission among occupants of the particular building space.
 16. Thesystem of claim 15, wherein controlling the HVAC system of the buildingto alter one or more environmental conditions of the particular buildingspace to reduce the likelihood of disease transmission among occupantsof the particular building space comprises controlling the HVAC systemof the building to increase a fresh air ventilation rate to theparticular building space.
 17. The system of claim 15, whereincontrolling the HVAC system of the building to alter one or moreenvironmental conditions of the particular building space to reduce thelikelihood of disease transmission among occupants of the particularbuilding space comprises controlling the HVAC system of the building tochange the air temperature in the particular building space.
 18. Thesystem of claim 15, wherein controlling the HVAC system of the buildingto alter one or more environmental conditions of the particular buildingspace to reduce the likelihood of disease transmission among occupantsof the particular building space comprises controlling the HVAC systemof the building to change the humidity in the particular building space.19. A system for disinfecting a space within a building, the buildingincluding a plurality of building spaces, the system comprising: aplurality of occupancy sensors distributed throughout each of at leastsome of the plurality of building spaces of the building; a plurality ofUV light sources distributed throughout each of at least some of theplurality of building spaces of the building, wherein when activated,the plurality of UV light sources disinfecting at least some surfaces ina corresponding building space; a controller operatively coupled to atleast some of the occupancy sensors and the plurality of UV lightsources, the controller configured to: monitor the occupancy sensors todetermine when one or more of the plurality of building spaces of thebuilding are unoccupied; activating one or more of the plurality of UVlight sources in one or more of the plurality of building spaces of thebuilding that are determined to be unoccupied; and monitor the occupancysensors to determine if one or more of the plurality of building spacesof the building where the one or more of the plurality of UV lightsources were activated become re-occupied, and if so, deactivating thecorresponding UV light sources.
 20. The system of claim 19, wherein thecontroller determines when a building space of the plurality of buildingspaces is currently indicated as being unoccupied by the occupancysensors and is expected to remain unoccupied for at least apredetermined period of time based at least in part on a historicaloccupancy pattern of the building space, and only then determining thatthe building space is unoccupied.